Sweet Safety Fail-Safe.

TopRamen · Apr 22, 2016

I watched this Video, and from what I can assume, the press is activated by both hands touching the contacts, which assure that both hands are somewhere other than in the press.
I really like it if that is the case.
Perhaps some of you Engineers or Machinist types can tell me if I'm correct in assuming that this is a fail safe safety device???

[video=youtube;6fkLFxn9nRA]https://www.youtube.com/watch?v=6fkLFxn9nRA[/video]

soopirV · Apr 22, 2016

I've seen controls like that quite often on shows like How it's Made, and yes, you're right- the press can only be operated if both switches are activated (not sure if they have to be simultaneous, or you can press one, then hit the other in sequential mode).

cavecentral · Apr 22, 2016

Two people to operate. Each with one hand inside. LOL.

TopRamen · Apr 22, 2016

cavecentral said:
Two people to operate. Each with one hand inside. LOL.

I think at least in my mindsim, that the contacts actually conduct a "Continuity Check" through the user. I guess if two fools want to hold hands and then lop off their remaining hands, then there's no cure for that.

cavecentral · Apr 22, 2016

TopRamen said:
I think at least in my mindsim, that the contacts actually conduct a "Continuity Check" through the user. I guess if two fools want to hold hands and then lop off their remaining hands, then there's no cure for that.

I thought about that too. Engineering's major failure, is the inability to predict how stupid people can actually be.

SwingWing · Apr 22, 2016

I used to operate a WWII era punch press that required two buttons to be pressed simultaneously, and a foot pedal activated the press. Not a new idea

Steve Shannon · Apr 22, 2016

TopRamen said:
I watched this Video, and from what I can assume, the press is activated by both hands touching the contacts, which assure that both hands are somewhere other than in the press.
I really like it if that is the case.
Perhaps some of you Engineers or Machinist types can tell me if I'm correct in assuming that this is a fail safe safety device???

[video=youtube;6fkLFxn9nRA]https://www.youtube.com/watch?v=6fkLFxn9nRA[/video]

That's an operator safety system, but not a fail safe device. A fail safe system is one that has been designed such that if it suffers a failure, the consequences of that failure are not hazardous. An example would be an access control system. If it were designed to be fail safe, in the event of a power failure the doors would unlock so people could get out. That same system could be designed as fail-secure, which would mean the doors would remain locked in case of a power failure.

[emoji1010] Steve Shannon, L3CC [emoji1010]

les · Apr 23, 2016

cavecentral said:
I thought about that too. Engineering's major failure, is the inability to predict how stupid people can actually be.

It is impossible to make things fool proof....

The fools are more clever them we are :wink:

tomsteve · Apr 23, 2016

SwingWing said:
I used to operate a WWII era punch press that required two buttons to be pressed simultaneously, and a foot pedal activated the press. Not a new idea

me,too. also there was a press i ran with just the hand switches. it didnt have to be simultaneous- i could hold the left or right button down and nothing would happen until the other was pushed. remove pressure from either switch during the cycle and the cycle stopped instantly.

another one similar with a guard that had to be in place and 2 hand switches pushed before cycling.

they were both wwII era presses

H_Rocket · Apr 23, 2016

cavecentral said:
I thought about that too. Engineering's major failure, is the inability to predict how stupid people can actually be.

We are pretty good. That said, we can't fix stupid.

The corollary is that the only result of intense effort to make something foolproof is a far more ingenuous fool.

TopRamen · Apr 23, 2016

Steve Shannon said:
That's an operator safety system, but not a fail safe device. A fail safe system is one that has been designed such that if it suffers a failure, the consequences of that failure are not hazardous. An example would be an access control system. If it were designed to be fail safe, in the event of a power failure the doors would unlock so people could get out. That same system could be designed as fail-secure, which would mean the doors would remain locked in case of a power failure.

[emoji1010] Steve Shannon, L3CC [emoji1010]

Good point.
Fail Safe was just the first phrase that came to mind.

K'Tesh · Apr 23, 2016

H_Rocket said:
We are pretty good. That said, we can't fix stupid.

The corollary is that the only result of intense effort to make something foolproof is a far more ingenuous fool.

And then there's the saying that if you make something so easy that any fool can use it, ONLY fools will use it.

Steve Shannon · Apr 23, 2016

K'Tesh said:
And then there's the saying that if you make something so easy that any fool can use it, ONLY fools will use it.

Yeah, but it's not true. Good interface design benefits everyone. A light switch is a good example. Fools and non-fools both use them. [emoji3]

[emoji1010] Steve Shannon, L3CC [emoji1010]

Pat_B · Apr 23, 2016

Way back in high school I had a printing class, and all of us were allowed to operate a paper cutter machine that worked the same way. I can't imagine they even allow those to be used in school nowadays. But the two handed button thing is standard on a lot of industrial machines.

AlfaBrewer · Apr 23, 2016

I learned early in my career that you can't idiot proof anything, only idiot limit. There will always be a more determined idiot.

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